This invention relates to microelectronics, and specifically to microwave frequency optical packages.
Microwave resonance in high-speed packages sometimes degrades the performance of the packages by deleteriously increasing the return loss of electrical signals fed into the package. The conventional approach to reduce the microwave resonance is to introduce thick sheets of resistive polymers, far from the launch site, onto the walls or lid of the packages to absorb microwaves after they are generated. However, with communication frequencies constantly increasing, this approach is insufficient to achieve the decrease in return loss desired, particularly at a time when the microwave spectrum technology is extending from 1 to 40 GHz and above.
A microwave package includes a housing having a moat formed in the housing to suppress microwave resonant energy. The moat may be filled with microwave absorbent material to further suppress microwave resonant energy.